Ellipsograph



J.,. BARACH lhLIPSOGRAPH March as ,1924,

Filed Jan. 8,. 1923 2 Sheets-Sheet 1 arch 18 1924. L487},

Ji. BARAQH ELL'IPSOGRAPH FiledJan. 8; 1923. 2 sh'eet-s she et 2 drawings, wherein- Patented Mar. 18,1924.

JOSEPH BAaAcH, or orncAeo, ILLINOIS.

ELLIPSOGBAPH.

Application filed January 8, 1923. Serial No. 611,521.

To all whom it may concern:

Be it known that I, Josnrrr BARAcH, a citi- I zen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements inEllipsographs, of which the following is a specification.

, This invention relates to ellipsogra-phs of that type consisting of a flexible scriber guide having its ends held at points coinciding with the foci of the ellipse. V

The invention has for its object to provide a novel and improved ellipsograph of the kind stated, which is adjustable to permit ellipses of various dimensions to be acculately and rapidly drawn, and which can also be used for drawing circles. j The object stated is attained by means of a combination and arrangement of parts to be hereinafter described and claimed, and in order that'the same may be better understood, reference is had to the accompanying Figure 1 is a perspective view of the instrument showing the operation of drawing an ellipse; Fig. 2 is an enlarged elevation of a frag ment of the instrument;

Figs. 3 and 4 are cross-sections on the line 3-3 and H, respectively, of Fig. 2; Fig. 5 is a plan view showing one end of j the instrument;

Fig. 6 is a cross-section on the line 66 of Fig. 5, and I Fig. 7 is an elevation of a pencilattachment used in connection with the instrument.

Referring specifically to the drawings, the body of the instrument is a straight bar 10 .of any suitable length according to the length of the major axis of the largest ellipse to be; drawn, and the ends of said bar are reduced and vertically apertured, as shown at 11, with a nut 12 fixed in said aperture to receive a thumb screw 13 having a pointed endfor insertion into the drawing board, table or other support of the sheet of paper or the like on which the ellipse is to be drawn, so that it will not be necessary for the operator to hold the bar down by hand.

The bar 10 is provided with a pair of slots 14' passing transversely therethrough and running in the direction of the length there- .latter being for a purpose tobe scribed. The other string holding device is of, and to the front and rear sides. of the bar, flush therewith, are secured metal reinforcement plates 15 which have slots registering with the slots 14a, In the slots 14 are slidably mounted the devices for holding'the string or other flexible scriber-guidlng means 16. One of these devicesconsists of a shank 17 having one end threaded to receive a wing nut 18, with a washer 19 interposed between the latter and the rear plate 15. The other end of the shank has a head 20 in contact with the front plate 15, and from said head extends a wing 21 provided with guide aperture 22 for the string 16, and a hook 23, the

presently dethe same as the one just described, except that itis not provided with the hook 23, its

wing with the string aperture, being shown at 24.

To the bottom of the bar 10, flush therewith, is secured a scale plate 25 which projects from the front face or side of the bar and has its graduations on the top of such projecting portion. Twosets of graduations are provided, the same being for the purpose of enabling the correct setting of the hereinbefore described string holding devices inthe slots l taccordingto the distance between the foci of the ellipse to be drawn.

On top of the bar 10, at one end thereof, is mounted a reel 26 for the string 16 and adj acent thereto the bar carries a guide-eye 27 for said string. A suitable winding gear 28 is provided for the reel 26, the same being fitted with a crank handle 29. The reel is also provided with a suitable pawl-and-ratchet device 30 for preventing rotation thereofin a direction to pay out thestring 16, and a slidable wedge-block 31 is associated with the pawl for holding the same clear of the ratchet when the string is to be unwound.

Adjacent to that end of the bar 10 opposite the end which carries the reel 26, is a hook 32, the purpose of which will be presently describe I j I v Midway between its ends,- the bar 10 has a means for supporting a transversely positioned scale bar 33 adapted to extend from v the scale plate 25, and provided witha hook 34 at its outer end. The bottom of the bar 10 has an undercut transverse recess 35 which is continued through the plate25, and in this 1 recess the bar 33 is adapted to be slidably seated for adjustment, it being locked in adjusted position by clamping screw 36 operated by a wing nut 37.

In the operation of the instrument, the string holding members are adjusted so that they are spaced apart a distance corresponding to the distance between the foci of the ellipse to be drawn. This adjustment of course axis of the ellipse. The scale bar 33 is to be adjusted to project a distance from the scale plate 25 corresponding to the length of the minor axis of the ellipse to be drawn. The bar 33 being positioned between the string holding members, the string will be paid out so that its portion which is between said members may be slipped over the hook '34:. The string passes loosely through the apertures 22 and 24, and its free end has a knot 16 whereby it is anchored to the hook 23. After being slipped over the hook 34, the string is to be drawn taut by operating the reel 26. The scale bar 33 is next backed to take it entirely clear of the string, the hook 34: being disengaged from the latter. The instrument is now ready for the drawing of the ellipse, this being done by placing the pencil or other scribing tool 38 inside the looped portion of the string and permitting the pencil to follow the same from one holding member to the other. By this operation only one half of the ellipse is drawn, but the other half can be drawn by reversing the instrument.

The instrument can also be used for drawing circles, and for this purpose the scale bar 25 has, midway between its ends, a string holding cleat 39. The string 16 will be looped and passed through the cleat so as to leave the loop projecting therefrom. The pencil will be inserted into the loop to be guided thereby in an arcuate path toform a semicircle. The string will, of course, be paid out a distance to permit the formation of a loop having a length corresponding to the radius of the circle to be drawn. After drawing the half circle, the instrument must be reversed to complete the circle.

7 The pencil 38 is fitted with a device for maintaining the string 16 at a uniform height when the pencil is stretching and running along the same to draw the ellipse or, the circle. This device is in the nature of a step collar 40 positioned near the tip of the pencil. On the shank of the pencil is secured by a set screw 41, a sleeve 42 from which projects a wing 13 carrying at its extremity the collar 40, the same being formed integral with the wing.

When the instrument is not in use, the scale bar 33 will be removed, and the knotted end 16 of the string 16 will be placed in the hook 32, so that when the string is drawn taut by operating. the reel 26, it will. lie out determines the length of the major of the way alongside the bar 10 and the scale plate 25. i

I claim:

1. An ellipsograph comprising a bar, a flexible seriber-guiding member, a pair of holders for said member adjustably supported by the bar, and a scale bar removably and adjustably supported by the firstmentioned bar to extend transversely and project from one side thereof, said scale bar having means for temporary attachment to its extremity of that portion of the scriberguiding member which is located between the aforesaid holders.

2. An ellipsograph comprising a bar, a flexible scriber guiding member, a reel carried by the bar for winding and unwinding said member, a pair of holders for said member adjustably supported by the bar, the free end thereof being attached to one holder and the other holder having a guide passage for the member, and a scale bar removably and adjustably supported by the first-mentioned bar to extend transversely from one side thereof, said scale bar having means for temporary attachment to its extremity of that portion of the scriber-guiding member which is located between the aforesaid holders.

3. An ellipsograph comprising a bar, a flexible scriber-guiding member, a reel carried by the bar for winding and unwinding said member, and a pair of holders for said member adjustably supported by the bar, said holders having guide passages for the scriber-guiding member, one of the holders having means for attachment of the free end of said member thereto, each of said holders having a guide passage for said member, means associated with one of said holders for engaging and retaining said member when the ellipsegraoh is in use, and means carried by said bar remote from said reel for engaging said member when the same is not in use.

4. An ellipsograph. comprising a bar, a flexible scriber-guiding member, a reel carried by the bar for winding and unwinding said member, a pair of holders for said member adjustably supported by the bar, said holders having guide passages for the scriber-guiding member, and one of the holders having" means for attachment of the free end of said member thereto, and a scale bar removably and adjustably supported by the first-mentioned bar to extend transversely from one side thereof, said scale bar having means for temporary attachment to ber adjustably supported by the bar, said holders having guide passages for the scriber-guiding member, and one of the holders having means for attachment of the 5 free end of said member thereto, a scale bar,

and means for adjustably supporting the I scale bar transversely of the first-mentioned 

